I am 9 weeks pregnant. I went to a restaurant and ordered a salad that came with blue cheese dressing. I asked for Ranch instead of the blue cheese. However, when it came out, it had the blue cheese crumbles on top. I just took off the crumbles and ate the salad. Now I am nervous about eating it! Should I be concerned about listeria?

I don't think you need to be actively worried about listeria unless you actually develop symptoms, which probably would have happened by now anyway. The immune system tends to attack the responsible microbe very aggressively as a rule, and you only ingested a tiny amount of potentially contaminated bleu cheese crumbs. While it is definitely wise to avoid the soft cheeses (as well as hotdogs, undercooked meats, etc.), especially when pregnant, I think it would be an extremely big coincidence if you did contract listeria from this very limited contact with the food in question.

Hope this helps, and I hope you have a safe and uneventful pregnancy. Congratulations!